Investigating respiration

• Respiration


  A chemical reaction which releases energy from food
• Respiratory system


  Exchanges the gases which are involved in respiration
• Investigating respiration


  1. Use limewater to detect carbon dioxide

  2. Breathe in through mouthpiece, breathe out through tube B

  3. Limewater in tube B turns cloudy due to more carbon dioxide in exhaled air
• Inhaled air contains 0.04% carbon dioxide, exhaled air contains 4%
• Exhaled air contains carbon dioxide

  100 times more than inhaled air
• Investigating heat production


  1. Use two vacuum flasks with germinating seeds

  2. Measure heat loss from respiration in germinating peas
• Aerobic respiration is investigated through an experiment which looks at heat loss in germinating peas as they respire